The State Department on Monday issued a worldwide travel alert over possible risks due to increased terrorism threats.

Current information suggests that the Islamic State (ISIS), Al-Qaeda, Boko Haram and other terrorist groups continue to plan terrorist attacks in multiple regions, the alert warned. 

“These attacks may employ a wide variety of tactics, using conventional and non-conventional weapons and targeting both official and private interests,” it continued. 

“Authorities believe the likelihood of terror attacks will continue as members of ISIL/Da’esh return from Syria and Iraq,” said the alert, which used the alternative acronyms for ISIS.

“Additionally, there is a continuing threat from unaffiliated persons planning attacks inspired by major terrorist organizations but conducted on an individual basis.  Extremists have targeted large sporting events, theatres, open markets, and aviation services. In the past year, there have been multiple attacks in France, Nigeria, Denmark, Turkey, and Mali. ISIL/Da’esh has claimed responsibility for the bombing of a Russian airliner in Egypt,” it continued.

The alert calls on U.S. citizens to exercise vigilance when in public places or using transportation.

“Be aware of immediate surroundings and avoid large crowds or crowed places.  Exercise particular caution during the holiday season and at holiday festivals or events.  U.S. citizens should monitor media and local information sources and factor updated information into personal travel plans and activities,”

The travel alert will expire on February 24, 2016.

A State Department official told Fox News on Monday that worldwide alerts “are issued periodically when there is a higher threat level,” and are not the same as a warning tied to a particular event, like an election or hurricane.

“We want folks to still travel, but just to exercise greater vigilance,” the official told the network.

The alert was issued a day after Belgium, in a crackdown on terrorism following the Paris attacks, arrested 16 terrorist suspects in raids across the country, though it did not apprehend Salah Abdeslam, who is wanted for his alleged role in carrying out the Paris attacks.

Belgian media later reported that Abdeslam had fled to Germany after being spotted by police near the city of Liege but managing to escape.